Through all the various testing I've done, mainly the shock testing, I've narrowed down a good combination of coatings and epoxies that seems to maximize the durability of the USB. I start with two layers of Silicon conformal coating.
|Silicon Conformal Coating a USB|
This is thin, flexible coating that gets into all the small nooks and crannies on the circuit board and even by itself seems to help a lot in minimizing damage caused by shock. Each coat requires at least a day to dry out.
|Drying Out the Conformal Coating|
Once the two conformal coatings are dry it is time for another two coatings of a thicker and more flexible insulating coating.
|Coating a USB in Insulating Varnish|
|Drying Out the Insulating Coating|
Next step is to just create an online store and actually start selling things!